Can MAD accretion disks launching structured jets explain both GRB and AGN engines? Magnetically arrested accretion disks launching structured jets in application to GRB and AGN engines

TL;DR

This paper investigates how magnetically arrested accretion disks can launch structured jets in both active galactic nuclei and gamma-ray bursts, explaining their emission properties and variability through 3D GR MHD simulations.

Contribution

It demonstrates that MAD accretion disks can produce persistent jets in AGNs and variable jets in GRBs, linking jet behavior to black hole parameters and accretion modes.

Findings

MAD scenario supports persistent jets in AGN engines.

MAD scenario produces variability patterns consistent with GRB observations.

Strong magnetic fields can quench jets, especially in GRBs.

Abstract

We explore the formation, energetics, and geometry of relativistic jets along with the variability of their central engine. We study both fast and slowly rotating black holes and address our simulations to active galaxy (AGN) centers and gamma ray burst (GRB) engines. The structured jets are postulated to account for emission properties of high energy sources across the mass scale, launched from stellar mass black holes in GRBs and from supermassive black holes in AGNs. Their active cores contain magnetized accretion disks and rotation of the Kerr black hole provides a mechanism for jet launching. This process works most effectively if the mode of accretion is magnetically arrested (MAD). In this mode, the modulation of jets launched from the engine is related to internal instabilities in the accretion flow that operate on smallest time and spatial scales. As these scales are related to the light-crossing time and the black hole gravitational radius, the universal model of jet-disk connection is expected to scale with the black hole mass. We investigate the jet-disk connection by means of 3D GR MHD simulations of the MAD accretion in Kerr metric. We quantify the variability of the disk by means of a Fourier analysis. We found that the evolution is governed by the physical parameters of the engine such as the black hole spin and disk size as well as its magnetization, and we applied our scenarios to typical types of sources in AGN and GRB classes. We found that the MAD scenario is applicable to AGN engines and supports persistent jet emission. It can also be applied to GRBs, as it gives the variability pattern roughly consistent with observations. However, in some cases, strong magnetic fields may lead to jet quenching, and this effect is found to be important mainly for GRB jets. We speculate that it may be related to the strength of magnetically driven winds from the GRB engines.